Columbia Gas TC — Pipeline Special Permit

2019-0202 Columbia Gas Transmission SPAF 2023, page 1Official PDFU.S. DEPARTMENT OF TRANSPORTATION PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION Special Permit Analysis and Findings Class 1 to 3 Location Special Permit Information: Docket Number: PHMSA-2019-02021,2 Requested By: Columbia Gas Transmission, LLC Operator ID#: 2616 Original Date Requested: October 15, 2019 Original Issuance Date: March 31, 2022 Amended Date: June 30, 2023 Code Section(s): 49 CFR 192.611(a) and (d) and 192.619(a) Purpose: The Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS), 3 provides this information to describe the facts of the subject special permit amendment application submitted by Columbia Gas Transmission, LLC (TCO), 4 to discuss any relevant public comments received with respect to the application, to present the engineering and safety analysis of the special permit application, and to make findings regarding whether the requested special permit should be granted and, if so, under what conditions. TCO requested that PHMSA waive 1 On June 22, 2022, TCO requested the addition of two (2) special permit segments 5 and 6 to its existing special permit. On November 30, 2022, TCO requested the addition of one (1) special permit segment 7. These segments are shown in Table 1 – Special Permit Segments 2 PHMSA published the special permit request in the Federal Register (87 FR 50691) for a 30-day public comment period from August 17, 2022, through September 16, 2022, for special permit segments 5 and 6. On January 5, 2023, PHMSA posted a notice of this special permit request for special permit segment 7, in the Federal Register (88 FR 908) to Docket No. PHMSA-2022-0166 with a closing date of February 6, 2023. Special permit segments 5, 6, and 7 have been included into special permit docket 2019-0202. 3 Throughout this special permit the usage of “PHMSA” or “PHMSA OPS” means the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration Office of Pipeline Safety. 4 TCO is a wholly owned, subsidiary of TC Energy. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 1 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 2compliance from the 49 Code of Federal Regulations (CFR) 192.611(a) and (d) and 192.619(a) for natural gas transmission pipeline segments, where the class location has changed from a Class 1 to a Class 3 location. Pipeline System Affected: This amendment of the special permit applies to the TCO request for a waiver from the class location change requirements in 49 CFR 192.611(a) and (d) and 192.619(a) for 3,101 feet (approximately 0.587 miles) of the 30-inch diameter gas transmission Line MC - Line VC Pipeline located in Montgomery County, Maryland; and Loudoun County, Virginia. Without this special permit, 49 CFR 192.611(a) would require TCO to replace the three (3) special permit segments with stronger pipe or reduce the pipeline maximum allowable operating pressure (MAOP) for a Class 1 to Class 3 location change. Pipe specifications including outside diameter, year installed, seam type, coating type, pipe grade, wall thickness, MAOP, minimum pressure test pressure, and pressure test factor based on the minimum test pressure are detailed in Table 1 – Pipe Specifications by Line Name. Table 1 – Pipe Specifications by Line Name Outside Min. Test Line Diameter Year Installed Name Seam Type Coating Type Grade Wall Thickness (inches) MAOP Pressure Pressure (psig) Test Factor (inches) (psig) MC/VC 30 1962 DSAW Asphalt X60 0.312 898 1,146 1.28 Note: DSAW is double submerged arc welded seam pipe. Special Permit Request: On June 22, 2022, and November 30, 2022, TCO applied to PHMSA for an amendment to its special permit seeking relief from 49 CFR 192.611(a) and (d) and 192.619(a) for the below listed special permit segments, where a class location change occurred from the original Class 1 to a Class 3 on the 30-inch diameter Line MC - Line VC Pipeline located in Montgomery County, Maryland; and Loudoun County, Virginia. Special Permit Segments: This special permit applies to the special permit segments in Table 2 – Special Permit Segments. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 2 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 3Table 2 – Special Permit Segments Special Outside Permit Line Diameter Name Length (feet) Start Survey Station (SS) End Survey Station (SS) County or Parish, State No. Year Seam MAOP Segment Number Dwellings Installed Type (psig) (inches) 5 30 Line VC 481 361+50 366+31 Loudoun, VA 3 1962 DSAW 898 6 30 Line MC 1,169 858+09 869+78 Montgomery, MD 2 1962 DSAW 898 7 30 Line MC 1,450 244+00 258+50 Montgomery, MD 3 1962 DSAW 898 Note: DSAW is double submerged arc welded seam pipe. Special Permit Inspection Area: The special permit inspection area is defined as the area that extends 220 yards on each side of the centerline as listed in Table 3 – Special Permit Inspection Area. Table 3 – Special Permit Inspection Area Special Special Permit Outside Start Survey Permit End Survey Station Length5 Inspection Diameter Line Name Station Segment(s) (SS) (miles) Area Number (inches) (SS) Included 1 1, 2, 3, 4, 5, 6, and 7 30 Line VC - Line MC 0+00 (Line VC) 1603+78 (Line MC) 40.5 Public Notice: On August 17, 2022, PHMSA posted a notice of this special permit request in the Federal Register (87 FR 50691) for special permit segments 5 and 6, with a closing date of September 16, 2022. PHMSA received no public comments concerning this special permit amendment. On January 5, 2023, PHMSA posted a notice of this special permit request for special permit segment 7, in the Federal Register (88 FR 908) to Docket No. PHMSA-2022-0166 with a closing date of February 6, 2023. PHMSA received public comment on the November 30, 2022, request and is addressing the comment received concerning this special permit amendment in the Final Environmental Assessment (FEA) and Finding of No Significant Impact (FONSI). The TCO special permit amendment application letter, Federal Register notice, Special Permit, FEA and FONSI, and all other pertinent documents are available for review in Docket No. 5 If the special permit inspection area footage does not extent from launcher to receiver then the special permit inspection area would need to be extended. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 3 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 4PHMSA-2019-0202 in the Federal Docket Management System (FDMS) located on the internet at www.Regulations.gov. Analysis: Background: On June 29, 2004, PHMSA published in the Federal Register (69 FR 38948) the criteria it uses for the consideration of applications for class location change waivers, now being granted or denied through a special permit. First, certain threshold requirements should be met on a pipeline special permit segment for a class location change special permit to be granted. Second, the age and manufacturing process of the pipe; system design, and construction; environmental, operating, and maintenance histories; and integrity management program elements are evaluated as significant criteria. These significant criteria are presented in matrix form and can be reviewed in the FDMS, Docket No. PHMSA–RSPA-2004-17401. Third, special permits will only be granted when pipe conditions and active integrity management provides a level of safety greater than or equal to a pipe replacement or pressure reduction. The operator’s federal pipeline safety regulation compliance history is also evaluated as part of the criteria matrix for acceptability prior to issuance of a special permit. Threshold Requirements: Each of the threshold requirements published by PHMSA in the June 29, 2004, Federal Register notice is discussed below for the TCO special permit request. 1) No pipeline segments in a class location changing to Class 4 location will be considered. • This special permit request is for special permit segments on the TCO 30-inch diameter Line MC – Line VC Pipeline, where a change has occurred from a Class 1 location to a Class 3 location. • TCO meets this requirement. 2) No bare pipe will be considered. • The TCO special permit segments are externally coated with asphalt enamel. • TCO has not reported any coating issues such as disbonded coating. • TCO meets this requirement. 3) No pipe containing wrinkle bends will be considered. • There are no wrinkle bends in the special permit segments. • TCO meets this requirement. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 4 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 54) No pipe segments operating above 72% of the specified minimum yield strength (SMYS) will be considered for a Class 3 special permit. • The special permit segments operate at or below 72% SMYS. • TCO meets this requirement. 5) Records must be produced that show a hydrostatic test to at least 1.25 x MAOP and 90% of SMYS. • The special permit segments on the Line MC – Line VC Pipeline was tested to at least 1.28 times the MAOP. • TCO meets this requirement. 6) Inline inspection (ILI) must have been performed with no significant anomalies identified that indicate systemic problems such as stress corrosion cracking (SCC). • TCO ran ILI tools on the Line MC – Line VC Pipeline in 2019 in the special permit inspection area. • TCO has not found any SCC indications in or within 20 miles of the special permit segment. • TCO meets this requirement. 7) Criteria for consideration of a class location change waiver, being considered through the special permit, published by PHMSA in the Federal Register (69 FR 38948), define a waiver inspection area (special permit inspection area) as up to 25 miles of pipe on either side of the waiver segment (special permit segment). • A special permit would be contingent upon TCO’s incorporation of the special permit segments in its written integrity management program as covered segments in a high consequence area (HCA) in accordance with 49 CFR 192.903 and to assess and remediate threats to the special permit inspection area. • TCO’s defined special permit inspection area is 40.5 miles in length. Criteria Matrix: The data submitted by TCO for the special permit segments has been compared to the class location change special permit criteria matrix. The data fall within the probable acceptance or the possible acceptance column of the criteria matrix, except for PHMSA enforcement findings which fall under the requires substantial justification. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 5 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 6• The special permit segments fall in the probable acceptance column of the criteria matrix for: o Design stress, pipe material, depth of pipe cover, test pressure, test failures, type service, pressure fluctuations, safety related conditions, leaks and failures, direct assessment, ILI type, ILI program, and damage prevention program. • The special permit segments fall in the possible acceptance column of the criteria matrix for: o Class 1 to 3 location, pipe manufacturer, pipe coating type (may shield cathodic protection (CP)), local geology, CP, and HCA program. • The special permit segments fall in the requires substantial justification column of the criteria matrix for: o TCO has identified issues in girth welds within the special permit segments and pipe girth weld records are not available. TCO will complete Special Permit Condition 6 – Girth Welds; o The coating type may shield CP when disbonded, causing SCC. 6 TCO will complete Special Permit Condition 7 – Stress Corrosion Cracking Threat; and o Inspection findings (Enforcement History) – PHMSA enforcements are in the “Past Enforcement History – January 1, 2011 through September 30, 2022” section below. Operational Integrity Compliance: To inform PHMSA’s decision about whether a special permit could provide a level of safety greater than or equal to a pipe replacement or pressure reduction and is consistent with pipeline safety, PHMSA reviewed this special permit request to understand the known type of integrity threats that are in the special permit segments and special permit inspection area. This integrity information was used to design special permit conditions to provide a systematic program to review and remediate the pipeline for safety concerns. Additional operational integrity review and remediation requirements are required by this special permit to ensure that the operator has an ongoing program to locate and remediate safety threats. These threats to integrity and safety 6 Two (2) types of SCC are found on pipelines: High pH (9 to 11) SCC and near-neutral pH (6 to 8) SCC. Coal tar and asphalt coatings that are disbonded are more prone to having SCC. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 6 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 7include any issues with the pipe coating quality, CP effectiveness, operations damage prevention program, pipe depth of soil cover, weld seam and girth weld integrity, anomalies in the pipe steel and welds, and material and structures either along or near the pipeline that could cause the CP system to be ineffective. PHMSA has carefully designed a comprehensive set of conditions that TCO must implement to comply with this special permit. Past Enforcement History – January 1, 2012 through January 22, 2023: From January 1, 2012, through January 22, 2023, TCO was cited in forty-four (44) enforcement actions with a total of $2,167,004 in assessed civil penalties. PHMSA initiated one (1) Corrective Action Order, eleven (11) Notices of Amendment, fifteen (15) Notices of Probable Violation, two (2) Safety Orders, and fifteen (15) Warnings Letter against TCO. TC Energy acquired TCO in 2016. Since TC Energy became owner of TCO, PHMSA has issued five (5) Notice of Amendments, three (3) Notice of Probable Violations, one (1) Safety Order, and twelve (12) Warning Letters with a total of $1,529,904 in collected penalties to TC Energy on the TCO pipeline system. Tables 4 and 5 below show PHMSA enforcement actions and civil penalties for TCO: Table 4: TCO Enforcement Matters from January 1, 2012 through January 22, 2023 Notice of Status Corrective Action Order Notice of Safety Probable Amendment Order Warning Letter Total Violation CLOSED 1 11 13 2 15 42 OPEN 0 0 2 0 0 2 Total 1 11 15 2 15 44 Table 5: TCO Enforcement Civil Penalty Status January 1, 2012 through January 22, 2023 Proposed Awaiting Order Assessed Withdrawn/Reduced Collected $2,293,804 $0 $2,167,004 $100,400 $2,167,004 Summary of Enforcement Findings for TCO includes: • Construction: Compliance with specifications or standards, Repair of Steel Pipe, General Inspection, and Installation of Pipe in a Ditch; Control Room Management: Alarm Management, Compliance and Deviations, Fatigue Mitigation, SCADA System Limitations, PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 7 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 8Provide Adequate Information, and Training Procedures; Atmospheric Corrosion Control: General and Monitoring; Corrosion Control: Corrosion Control Records; External Corrosion Control: Buried Pipe Post 1971, Interference Currents, and Monitoring; Design: Compressor Stations Additional safety equipment and Supports and Anchors; Enforcement Procedures: Inspections and Investigations; Integrity Management (IM): Elements and Implementation, Preventative and Mitigative Measures, and HCA Identification; OME Procedural Manual: Abnormal Operations, General, and Maintenance and normal operations; Maintenance: General, Line Markers, Pressure Limiting and Regulating Stations, Prevention of Accidental Ignition, Patrolling, Record keeping, and Leak Surveys; Operations: Alternative MAOP, Emergency Plans, General, MAOP-Steel or Plastic, and Procedures; Operator Qualification: Qualification Program; Reporting: Filing Safety Related Condition Report (SRCR) and GTGG Annual Reports; Test Requirements: General and SMYS > 30% (at or above the test pressure for at least 8 hours); Gas Transportation: Class Locations, Gathering Line Requirements, and Underground natural gas storage facilities; Welding: Inspection and Test of Welds. • 49 CFR 190.203, 191.17, 191.22, 191.25, 192.5, 192.9, 192.12, 192.161, 192.171, 192.241, 192.303, 192.305, 192.309, 192.319, 192.455, 192.465, 192.473, 192.479, 192.481, 192.491, 192.503, 192.505, 192.603, 192.605, 192.615, 192.619, 192.620, 192.631, 192.703, 192.705, 192.706, 192.707, 192.709, 192.743, 192.805, 192.905, 192.907, and 192.935. Table 6 below shows PHMSA’s enforcement actions and civil penalties for TCO and the specific 49 CFR Parts 191 and 192 violations: Table 6: Summary of Enforcement Findings from TCO January 1, 2012 to January 22, 2023 Notice of Amendment Construction 1 Control Room Management 13 Integrity Management 1 OME Procedural Manual 4 Operation and/or Maintenance 7 Operator Qualification 2 Transportation of Gas 10 Notice of Amendment Total: 38 Notice of Probable Violation Construction 2 Corrosion Control 9 Design 1 Fire Protection 1 Integrity Management 1 OME Procedural Manual 4 Operation and/or Maintenance 5 Reporting 2 Test Requirements 1 PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 8 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 9Transportation of Gas 1 Welding of Steel in Pipelines 1 Notice of Probable Violation Total: 28 Warning Letter Corrosion Control 2 Design 1 Enforcement and Regulatory Procedures 1 OME Procedural Manual 6 Operation and/or Maintenance 13 Reporting 3 Transportation of Gas 3 Warning Letter Total: 27 Grand Total: 93 Summary of Enforcement Findings for TC Energy – ANR, CGT, GLGTC, PNGTS, and TCO: From January 1, 2012 through January 22, 2023, TC Energy, the operator of PNGTS, was cited in 73 enforcement actions with a total of $2,978,004 in assessed civil penalties on its ANR Pipeline Company (ANR) (OPID 405), Columbia Gulf Transmission (CGT) (OPID 2620), Columbia Gas Transmission (TCO) (OPID 2616), Great Lakes Gas Transmission Company (GLGTC) (OPID 6660), and Portland Natural Gas System (PNGTS) (OPID 31145) pipeline systems. PHMSA issued three (3) Corrective Action Orders, 18 Notices of Amendment, 24 Notices of Probable Violation, two (2) Safety Orders and 26 Warning Letters to TC Energy. Tables 7 and 8 below show PHMSA’s enforcement actions and civil penalties for TC Energy on these pipeline systems – ANR, CGT, TCO, GLGTC, and PNGTS pipeline systems. Table 7: TC Energy Enforcement Matters from January 1, 2012 through January 22, 2023 Notice of Status Corrective Action Order Notice of Safety Probable Amendment Order Warning Letter Total Violation CLOSED 3 18 22 2 26 71 OPEN - - 2 - - 2 Total 3 18 24 2 26 73 Table 8: TC Energy Enforcement Civil Penalty Status January 1, 2012 through January 22, 2023 Proposed Awaiting Order Assessed Withdrawn/Reduced Collected $3,161,004 $0 $2,978,004 $156,600 $2,978,004 The type of 49 CFR Part 192 enforcement violations against TC Energy on these five (5) pipeline PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 9 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 10systems from January 1, 2012 through January 22, 2023 were as follows: Summary of Enforcement Endings for ANR, CGT, TCO, GLGTC, and PNGTS includes: Construction: Compliance with specifications or standards, General Inspection, Installation of Pipe in a Ditch; Control Room Management: Alarm Management, Compliance and Deviations, Fatigue Mitigation, Provide Adequate Information (Point to Point Checks), Roles & Responsibilities, SCADA System Limitations, Training, and Training Procedures; Atmospheric Corrosion Control: General and Monitoring; Corrosion Control: Corrosion Control Records; External Corrosion Control: Buried Pipe Post 1971, Interference Currents, Monitoring, and Test Leads; Design: Compressor Station Design & Construction, Compressor Stations Additional Safety Equipment, Compressor Stations Emergency Shutdown, and Supports and Anchors; Drug and Alcohol: Alcohol Tests Required and Drug Testing Required; Enforcement Procedures: Inspections and Investigations, IM: Addressing Integrity Issues, Elements and Implementation, Change to IM Plan, HCA Identification, Preventative and Mitigative Measures, Program Elements, and Requirements for SCCDA; OME Procedural Manual: General, Maintenance and normal operations, Abnormal operations, Alternative MAOP, and SRCR; Maintenance: Abandonment or Deactivation of Facilities, Compressor Stations-Gas Detection, Compressor stations-inspection and testing of relief devices, Compressor stations-Storage of Combustible Materials, General, Line Markers, Pressure Limiting and Regulating Stations-Inspection and Testing, Pressure Limiting and Regulating Stations-Relief Devices, Prevention of Accidental Ignition, Procedures, Remedial Measures, Patrolling, Record keeping, Repair Procedures, and Valve Maintenance Transmission Lines; Operations: Change in Class Location (Required Study), Emergency Plans, General, MAOP-Steel or Plastic, Odorization of Gas, Procedures, Transfer Procedures, and Underwater Inspection to Identify Gulf of Mexico Pipeline Hazards; Operator Qualification: Qualification Program; Public Awareness: Activities for advising affected municipalities, Comprehensive Media, Develop and Implement Public Awareness, Justification for not following API RP 1162, Specifics addressing the Public; Reporting: Filing SRCR, Annual Reports, Immediate Reporting Incident, and National Registry of Pipeline and LNG Operators; Test Requirements: General; Gas Transportation: Class Locations, Gathering Line Requirements, Underground Natural Gas Storage Facilities; Welding: Inspection and Test of Welds, Procedures, and Qualification of Welders, • 49 CFR 190.203, 191.3, 191.5, 191.15, 191.17, 191.22, 191.25, 192.5, 192.9, 192.12, PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 10 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 11192.161, 192.163, 192.167, 192.171, 192.201, 192.225, 192.241, 192.303, 192.305, 192.309, 192.319, 192.455, 192.465, 192.471, 192.473, 192.479, 192.481, 192.491, 192.603, 192.605, 192.609, 192.612, 192.615, 192.616, 192.619, 192.625, 192.631, 192.703, 192.705, 192.707, 192.709, 192.727, 192.731, 192.735, 192.736, 192.739, 192.743, 192.745, 192.751, 192.805, 192.905, 192.907, 192.909, 192.911, 192.933, and 192.935. Table 9 below gives a complete summary of the findings and the specific 49 CFR Part 191 and 192 violation: Table 9: Summary of Enforcement Findings for ANR, TCO, CGT, GLGT, and PNGTS January 1, 2012 through January 22, 2023 Notice of Amendment Construction 1 Control Room Management 16 Integrity Management 5 OME Procedural Manual 9 Operation and/or Maintenance 7 Operator Qualification 2 Public Awareness 6 Transportation of Gas 10 Welding of Steel in Pipelines 1 Notice of Amendment Total: 57 Notice of Probable Violation Construction 2 Corrosion Control 11 Design 3 Drug and Alcohol 2 Integrity Management 6 OME Procedural Manual 6 Operation and/or Maintenance 16 Public Awareness 1 Reporting 8 Test Requirements 1 Transportation of Gas 1 Welding of Steel in Pipelines 1 Notice of Probable Violation Total: 58 Warning Letter Control Room Management 5 Corrosion Control 4 Design 2 Enforcement and Regulatory Procedures 1 Integrity Management 2 OME Procedural Manual 11 Operation and/or Maintenance 19 Operator Qualification 1 Reporting 8 Transportation of Gas 5 Welding of Steel in Pipelines 1 Warning Letter Total: 59 Grand Total: 174 Findings: Based on the information submitted by TCO and PHMSA’s analysis of the technical, operational, and safety issues, PHMSA finds that granting this special permit to TCO to operate special permit segments on the 30-inch diameter Line MC – Line VC Pipeline located in Montgomery County, Maryland, and Loudoun County, Virginia is consistent with pipeline safety. PHMSA has designed special permit conditions to effectively assess and remediate threats to the special permit segments and special permit inspection area, including assessments to evaluate PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 11 of 12#

2019-0202 Columbia Gas Transmission SPAF 2023, page 12pipe girth welds that have not been non-destructively tested and for SCC. To ensure TCO properly implements the special permit conditions, TCO will be required to give PHMSA an annual review of their compliance with the special permit. PHMSA finds that no significant negative impact to human safety and the environment will result from the issuance and full implementation of this amendment of a special permit that waives the requirements of 49 CFR 192.611 for class location changes from Class 1 to a Class 3 location. This permit amendment requires TCO to implement the special permit conditions that include safety requirements on the operations, maintenance, and integrity management of the special permit segments and the special permit inspection area. Completed in Washington DC on: June 30, 2023 Prepared by: PHMSA - Engineering and Research Division Final Page of the Special Permit Analysis and Findings PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland and Virginia Page 12 of 12#

2019-0202 - Columbia Gas (TCO) - Class 1 to 3 - MD VA - LOD - Amended - 06302023, page 1Official PDFU.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 June 30, 2023 Stanley Chapman Executive VP and President of U.S. Natural Gas Pipelines TC Energy 700 Louisiana Street, Suite 300 Houston, Texas 77002 Re: Docket No. PHMSA-2019-0202 Special Permit from March 31, 2022, to March 31, 2032 Dear Mr. Chapman: On June 22, 2022, and November 30, 2022, pursuant to 49 Code of Federal Regulations (CFR) § 190.341, Columbia Gas Transmission, LLC (TCO)1 applied to the Pipeline and Hazardous Materials Safety Administration (PHMSA) for a special permit. TCO requested to amend the previously granted special permit at Docket No. PHMSA 2019-0202 to waive compliance with 49 CFR §§ 192.611(a) and (d) and 192.619(a) for Class 1 to Class 3 location changes for an additional 0.587 miles of the 30-inch diameter Line MC – Line VC pipeline (Pipeline). The Pipeline is located in Montgomery County, Maryland, and Loudoun County, Virginia. A gas transmission pipeline operator is required by 49 CFR § 192.611 to confirm or revise the maximum allowable operating pressure of a pipeline segment where the class location has changed as defined in 49 CFR § 192.5. On August 17, 2022, PHMSA published a Federal Register notice (87 FR 50691) announcing the Special Permit Request for Docket No. PHMSA-2019-0202. On January 5, 2023, PHMSA published an additional Federal Register notice (88 FR 908) for the second request under separate Docket No. PHMSA-2022-0166. The Special Permit Request letter, Final Environmental Assessment (FEA) and Finding of No Significant Impact (FONSI), Special Permit Analysis and Findings (SPAF), and all other pertinent documents for this special permit have been combined and are available in Docket No. PHMSA-2019-0202 in the Federal Docket 1 Columbia Gas Transmission, LLC is a subsidiary of TC Energy.#

2019-0202 - Columbia Gas (TCO) - Class 1 to 3 - MD VA - LOD - Amended - 06302023, page 2Management System located at www.regulations.gov. 2 PHMSA received public comment on these special permit requests and has addressed such in the Final Environmental Assessment. Subject to the stated terms and conditions, PHMSA grants the amendment to the special permit (enclosed) issued on March 31, 2022, based on the information provided by TCO and the findings set forth in the SPAF, FEA, and FONSI. This special permit provides relief from certain provisions of the Federal pipeline safety regulations for the Pipeline and requires TCO to comply with conditions and limitations designed to maintain pipeline safety as defined in the special permit. In accordance with 49 CFR § 190.341(j), PHMSA reserves the right to revoke, suspend, or modify this special permit if circumstances occur in which its continuance would be inconsistent with pipeline safety. If TCO elects not to implement the special permit conditions for the segments identified in the amended special permit, TCO must notify PHMSA within 60 days and comply with 49 CFR § 192.611(a) within 18 months of the date of this letter granting the special permit amendment. My staff would be pleased to discuss this special permit or any other regulatory matter with you. Mary McDaniel, Acting Director of PHMSA Engineering and Research Division, may be contacted at (713) 272-2847, on technical matters; and Robert Burrough, Director, Office of Pipeline Safety, Eastern Region may be contacted at (609) 771-7809, for operational matters specific to this special permit. Sincerely, Alan K. Mayberry Associate Administrator for Pipeline Safety Enclosure: Special Permit – PHMSA-2019-0202 2 https://www.regulations.gov/docket?D=PHMSA-2019-0202. PHMSA will also post all documents relevant to the November 30, 2022, request in Docket No. PHMSA-2022-0166, the docket number for which that request was initially assigned.Special Permit Amendment: PHMSA-2019-0202 – Columbia Gas Transmission, LLC Letter of Decision – Class 1 to 3 Locations – Maryland and Virginia Page 2 of 2#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 1Official PDFU.S. DEPARTMENT OF TRANSPORTATION PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION Special Permit Analysis and Findings Class 1 to 3 Location Special Permit Information: Docket Number: PHMSA-2019-0202 Requested By: Columbia Gas Transmission, LLC Operator ID#: 2616 Original Date Requested: October 15, 2019 Original Issuance Date: March 31, 2022 Effective Dates: March 31, 2022 to March 31, 2032 Code Section(s): 49 CFR 192.611 Purpose: The Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS), 1 provides this information to describe the facts of the subject special permit application submitted by Columbia Gas Transmission, LLC (TCO), 2 to discuss any relevant public comments received with respect to the application, to present the engineering and safety analysis of the special permit application, and to make findings regarding whether the requested special permit should be granted and, if so, under what conditions. TCO requested that PHMSA waive compliance from the 49 Code of Federal Regulations (CFR) 192.611 for natural gas transmission pipeline segments, where the class location has changed from a Class 1 to a Class 3 location. 1 Throughout this special permit the usage of “PHMSA” or “PHMSA OPS” means the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration Office of Pipeline Safety. 2 TCO is a wholly-owned, subsidiary of TC Energy. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 1 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 2Pipeline System Affected: This special permit application applies to the TCO request for a waiver from the class location change requirements in 49 CFR 192.611 for 10,801 feet (approximately 2.046 miles) of the 30- inch diameter gas transmission Line MC Pipeline located in Montgomery County, Maryland. Without this special permit, 49 CFR 192.611(a) would require TCO to replace the four (4) special permit segments with stronger pipe or reduce the pipeline maximum allowable operating pressure (MAOP) for a Class 1 to Class 3 location change. Pipe specifications including outside diameter, year installed, seam type, coating type, pipe grade, wall thickness, MAOP, minimum pressure test pressure, and pressure test factor based on the minimum test pressure are detailed in Table 1 – Pipe Specifications by Line Name. Table 1 – Pipe Specifications by Line Name Outside Min. Test Line Diameter Year Installed Name Seam Type Coating Type Grade Wall Thickness (inches) MAOP Pressure Pressure (psig) Test Factor (inches) MC 30 1962 SAW Asphalt X60 0.312 / 0.375 898 (psig) 1,275 1.42 Note: SAW is single submerged arc welded seam pipe. Special Permit Request: On October 15, 2019, TCO applied to PHMSA for a special permit seeking relief from 49 CFR 192.611 for the below listed special permit segments, where a class location change occurred from the original Class 1 to a Class 3 on the 30-inch diameter Line MC Pipeline located in Montgomery County, Maryland. Special Permit Segments: This proposed special permit applies to the special permit segments in Table 2 – Special Permit Segments. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 2 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 3Table 2 – Special Permit Segments Material Special Permit Outside Records – Line Length Start Survey End Survey County or Parish, No. Year Seam MAOP Diameter Condition Segment Number Name (feet) Station (SS) Station (SS) State Dwellings Installed Type (psig) (inches) 13(d) 1 30 Line MC 3,453 553+57 588+10 Montgomery, MD 20 1962 SAW 898 required Yes 2 30 Line MC 2,685 596+56 623+41 Montgomery, MD 35 1962 SAW 898 Yes 3 30 Line MC 3,415 281+49 315+64 Montgomery, MD 74 1962 SAW 898 Yes3 4 30 Line MC 1,248 337+91 350+39 Montgomery, MD 2 1962 SAW 898 Yes Note: SAW is single submerged arc welded seam pipe. Special Permit Inspection Area: The special permit inspection area is defined as the area that extends 220 yards on each side of the centerline as listed in Table 3 – Special Permit Inspection Area. Table 3 – Special Permit Inspection Area Special Special Permit Outside Permit Inspection Diameter Line Name Start Survey Station End Survey Station (SS) Length4 (miles) Area Number Segment(s) Included (inches) (SS) 1 1, 2, 3, and 4 30 Line VC - Line MC 0+00 (Line VC) 1603+78 (Line MC) 40.5 The special permit inspection area is located in Loudoun County, Virginia, and Montgomery and Howard Counties, Maryland.5 Figures 1 through 3 are maps showing the 30-inch diameter Line VC – Line MC Pipeline special permit segments, special permit inspection area, and class locations. Public Notice: On September 8, 2020, PHMSA posted a notice of this special permit request in the Federal Register (85 FR 55574) with a closing date of October 8, 2020. PHMSA received an anonymous comment recommending that PHMSA not issue any special permits and take other actions related to energy legislation. PHMSA’s statute and regulations provide pipeline operators the opportunity to apply for special permits and PHMSA uses the conditions placed on permit grants 3 TVC material records for 3,377 feet of the original 1962 pipe from 281+53 to 314+32 and 314+66 to 315+64 were not provided. 4 If the special permit inspection area footage does not extent from launcher to receiver then the special permit inspection area would need to be extended. 5 The special permit inspection area includes the special permit segments. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 3 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 4to protect public safety and the environment. PHMSA is an executive agency that does not take legislative actions. PHMSA has reviewed this special permit application to ensure the special permit conditions address pipeline safety and integrity threats to the pipeline in the special permit segments and special permit inspection area. The special permit will require TCO’s Operations and Maintenance (O&M) Manual and Procedures to provide a systematic program to review and remediate the pipeline for safety concerns. Additional operational integrity reviews and remediation requirements will be required by this special permit for these special permit segments for Class 1 to 3 location changes. The TCO special permit application letter, Federal Register notice, Special Permit, Final Environmental Assessment (FEA) and Finding of No Significant Impact (FONSI), and all other pertinent documents are available for review in Docket No. PHMSA-2019-0202 in the Federal Docket Management System (FDMS) located on the internet at www.Regulations.gov. Analysis: Background: On June 29, 2004, PHMSA published in the Federal Register (69 FR 38948) the criteria it uses for the consideration of applications for class location change waivers, now being granted or denied through a special permit. First, certain threshold requirements should be met on a pipeline special permit segment for a class location change special permit to be granted. Second, the age and manufacturing process of the pipe; system design, and construction; environmental, operating, and maintenance histories; and integrity management program elements are evaluated as significant criteria. These significant criteria are presented in matrix form and can be reviewed in the FDMS, Docket No. PHMSA–RSPA-2004-17401. Third, special permits will only be granted when pipe conditions and active integrity management provides a level of safety greater than or equal to a pipe replacement or pressure reduction. The operator’s federal pipeline safety regulation compliance history is also evaluated as part of the criteria matrix for acceptability prior to issuance of a special permit. Threshold Requirements: Each of the threshold requirements published by PHMSA in the June 29, 2004, Federal Register notice is discussed below for the TCO special permit request. 1) No pipeline segments in a class location changing to Class 4 location will be considered. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 4 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 5• This special permit request is for special permit segments on the TCO 30-inch diameter Line MC Pipeline, where a change has occurred from a Class 1 location to a Class 3 location. • TCO meets this requirement. 2) No bare pipe will be considered. • The TCO special permit segments are externally coated with asphalt. • TCO has not reported any coating issues such as disbonded coating. • TCO meets this requirement. 3) No pipe containing wrinkle bends will be considered. • There are no wrinkle bends in the special permit segments. • TCO meets this requirement. 4) No pipe segments operating above 72% of the specified minimum yield strength (SMYS) will be considered for a Class 3 special permit. • The special permit segments operate at or below 72% SMYS. • TCO meets this requirement. 5) Records must be produced that show a hydrostatic test to at least 1.25 x MAOP and 90% of SMYS. • The special permit segments on the Line MC Pipeline was tested to at least 1.42 times the MAOP. • TCO meets this requirement. 6) Inline inspection (ILI) must have been performed with no significant anomalies identified that indicate systemic problems such as stress corrosion cracking (SCC). • TCO ran ILI tools on the Line MC Pipeline in 2019 in the special permit inspection area. • TCO has not found any SCC indications in or within 20 miles of the special permit segment. • TCO meets this requirement. 7) Criteria for consideration of a class location change waiver, being considered through the special permit, published by PHMSA in the Federal Register (69 FR 38948), define a waiver inspection area (special permit inspection area) as up to 25 miles of pipe on either side of the waiver segment (special permit segment). PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 5 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 6• A special permit would be contingent upon TCO’s incorporation of the special permit segments in its written integrity management program as covered segments in a high consequence area (HCA) in accordance with 49 CFR 192.903 and to assess and remediate threats to the special permit inspection area. • TCO’s defined special permit inspection area is 40.5 miles in length. Criteria Matrix: The data submitted by TCO for the special permit segments has been compared to the class location change special permit criteria matrix. The data fall within the probable acceptance or the possible acceptance column of the criteria matrix, except for PHMSA enforcement findings which fall under the requires substantial justification. • The special permit segments fall in the probable acceptance column of the criteria matrix for: o Design stress, pipe material, depth of pipe cover, test pressure, test failures, type service, pressure fluctuations, safety related conditions, leaks and failures, direct assessment, ILI type, ILI program, and damage prevention program. • The special permit segments fall in the possible acceptance column of the criteria matrix for: o Class 1 to 3 location, pipe manufacturer, pipe coating type (may shield cathodic protection (CP)), local geology, CP, and HCA program. • The special permit segments fall in the requires substantial justification column of the criteria matrix for: o TCO has identified issues in girth welds within the special permit segments and pipe girth weld records are not available. TCO will complete Special Permit Condition 6 – Girth Welds; o The coating type may shield CP when disbonded, causing SCC. 6 TCO will complete Special Permit Condition 7 – Stress Corrosion Cracking Threat; and 6 Two (2) types of SCC are found on pipelines: High pH (9 to 11) SCC and near-neutral pH (6 to 8) SCC. Coal tar and asphalt coatings that are disbonded are more prone to having SCC. PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 6 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 7o Inspection findings (Enforcement History) – PHMSA enforcements are in the “Past Enforcement History – January 1, 2011 through June 21, 2021” section below. Operational Integrity Compliance: To inform PHMSA’s decision about whether a special permit could provide a level of safety greater than or equal to a pipe replacement or pressure reduction and is consistent with pipeline safety, PHMSA reviewed this special permit request to understand the known type of integrity threats that are in the special permit segments and special permit inspection area. This integrity information was used to design special permit conditions to provide a systematic program to review and remediate the pipeline for safety concerns. Additional operational integrity review and remediation requirements are required by this special permit to ensure that the operator has an ongoing program to locate and remediate safety threats. These threats to integrity and safety include any issues with the pipe coating quality, CP effectiveness, operations damage prevention program, pipe depth of soil cover, weld seam and girth weld integrity, anomalies in the pipe steel and welds, and material and structures either along or near the pipeline that could cause the CP system to be ineffective. PHMSA has carefully designed a comprehensive set of conditions that TCO must implement to comply with this special permit. Past Enforcement History – January 1, 2011 through June 21, 2021: From January 1, 2011, through June 21, 2021, TCO was cited in forty (40) enforcement actions with a total of $752,400 in assessed civil penalties. PHMSA initiated one (1) Corrective Action Order, ten (10) Notices of Amendment, thirteen (13) Notices of Probable Violation, three (3) Safety Orders, and eleven (11) Warnings Letter against TCO. TC Energy acquired TCO in 2016. Since TC Energy became owner of TCO, PHMSA has issued four (4) Notice of Amendments, one (1) Notice of Probable Violations, one (1) Safety Order, and seven (7) Warning Letters with a total of $47,500 in collected penalties to TC Energy on the TCO pipeline system. Tables 4 and 5 below show PHMSA enforcement actions and civil penalties for TCO: PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 7 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 8Table 4: TCO Enforcement Matters from January 1, 2011, through June 21, 2021 Corrective Notice of Notice of Status Action Order Amendment Probable Safety Warning Violation Order Letter Total CLOSED 1 11 12 3 12 39 OPEN 0 1 0 1 Total 1 13 3 12 40 Table 5: TCO Enforcement Civil Penalty Status January 1, 2011 through June 21, 2021 Proposed Awaiting Order Assessed Withdrawn/Reduced Collected $879,200 $0 $752,400 $126,800 $752,400 From January 1, 2011, through June 21, 2021, PHMSA initiated the enforcement cases outlined in Tables 6 and 7 against the four (4) pipeline companies owned by TC Energy, the operator of TCO. TC Energy owns the ANR Pipeline Company (ANR), Columbia Gas Transmission, LLC (TCO), Columbia Gulf Transmission, LLC (CGT), and Great Lakes Gas Transmission Company (GLGT) pipeline systems (Operator identification #s 405, 2616, 2620, and 6660). TC Energy acquired the TCO and CGT pipeline systems in 2016. Table 6: Enforcement Matters from January 1, 2011 through June 21, 2021 ANR, TCO, CGT, and GLGT through June 21, 2021 Notice of Status Corrective Notice of Action Order Safety Amendment Probable Warning Violation Order Letter Total CLOSED 3 17 23 3 21 67 OPEN 0 0 3 0 3 Total 3 17 26 3 21 70 Table 7: Enforcement Civil Penalty Status for ANR, TCO, CGT, and GLGT January 1, 2011 through June 21, 2021 Proposed Awaiting Order Assessed Withdrawn/Reduced Collected $1,881,600 $0 $1,678,000 $203,600 $1,678,000 PHMSA-2019-0202 - Columbia Gas Transmission, LLC Page 8 of 12 Special Permit Analysis and Findings - Maryland#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 9The type of 49 CFR Part 192 enforcement violations against TC Energy on these four (4) pipeline systems from January 1, 2011 through June 21, 2021 were as follows: 49 CFR, 190.203, 191.15, 191.17, 191.22, 191.23, 191.25, 191.5, 192.107, 192.12, 192.161, 192.163, 192.167, 192.171, 192.201, 192.225, 192.227, 192.241, 192.303, 192.305, 192.309, 192.319, 192.455, 192.463, 192.465, 192.467, 192.471, 192.473, 192.475, 192.477, 192.479, 192.481, 192.491, 192.503, 192.505, 192.603, 192.605, 192.609, 192.612, 192.615, 192.616, 192.619, 192.620, 192.625, 192.631, 192.703, 192.705, 192.707, 192.709, 192.711, 192.727, 192.731, 192.735, 192.736, 192.739, 192.743, 192.745, 192.751, 192.805, 192.905, 192.907, 192.909, 192.911, 192.929, 192.933, 192.935, 192.949, 193.2011, 193.2017, 193.2503, 193.2509, 193.2513, 193.2605, 193.2609, 193.2637, 193.2801, 193.2903, 199.105, and 199.225. Findings: Based on the information submitted by TCO and PHMSA’s analysis of the technical, operational, and safety issues, PHMSA finds that granting this special permit to TCO to operate special permit segments on the 30-inch diameter Line MC Pipeline located in Montgomery County, Maryland, is consistent with pipeline safety. TCO’s enforcement record since 2016 does not reflect sustained and substantial noncompliance with 49 CFR Part 192. PHMSA has designed special permit conditions to effectively assess and remediate threats to the special permit segments and special permit inspection area, including assessments to evaluate pipe girth welds that have not been non-destructively tested and any SCC. To ensure TCO properly implements the special permit conditions, TCO will be required to give PHMSA an annual review of their compliance with the special permit. PHMSA finds that no significant negative impact to human safety and the environment will result from the issuance and full implementation of a special permit that waives the requirements of 49 CFR 192.611 for class location changes from Class 1 to a Class 3 location. This permit requires TCO to implement the special permit conditions that include safety requirements on the operations, maintenance, and integrity management of the special permit segments and the special permit inspection area. Completed in Washington DC on: March 31, 2022 Prepared by: PHMSA - Engineering and Research Division PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 9 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 10Figure 1 – 30-inch TCO Line VC & MC Route Map Special Permit Segments and Inspection Area PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 10 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 11Figure 2 – 30-inch TCO Line MC Route Map Special Permit Segments 1 and 2 PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 11 of 12#

2019-0202 - Columbia Gas Trans (TCO) - Class 1 to 3 - MD - SPAF - 03-31-2022, page 12Figure 3 – 30-inch TCO Line MC Route Map Special Permit Segments 3 and 4 Final Page of the Special Permit Analysis and Findings PHMSA-2019-0202 – Columbia Gas Transmission, LLC Special Permit Analysis and Findings – Maryland Page 12 of 12#